Transmission housings frequently are divided into sections, with different components of the transmission being provided in different sections. For example, it is fairly common to have a partition separating the final reduction gear/differential from the main gear shift portion of the transmission.
In this type of housing, one problem which can arise is that oil can flow undesirably from one chamber into the other, for example, while the vehicle is on a slope. This can create unacceptably high oil levels in one part of the housing and unacceptably low oil levels in the gear shift case.
Various mechanisms for dealing with such situations have been proposed. One technique for dealing with this problem is to completely separate the two housings. Another is to provide a pump to pump oil from the chamber in which it accumulates to the chamber where it is low. Such a technique is shown, e.g., in U.S. Pat. No. 4,529,061 (Glasrud et al.). This, however, has the disadvantage that a fairly large diameter connection is required for oil flow and the oil tends to accumulate contaminants, which can clog the line.
Accordingly, it is the purpose of the present invention to provide a system for balancing oil levels which does not require an oil pump to move the oil from one chamber to the other.